Compressor



y 1944- \MQWISHART 2,347,862 I COMPRESSOR Filed June 8(1940,fiSheets-Sheet 1 Wyn 70R.-

May 2, 1944.

W. W. WISHART COMPRESSOR Filed June 8, 1940 4 Sheets-Sheet 2 I 4 //vv/vTORI WILL/AM w w/sHAR y 1944- 4 w. w. WISHART 2,347,862 I COMPRESSQORFiled June 8, 1940 4 Sheets-Sheet 3 AT X w. w. WISHART' May 2; 1944.2,347,862 I v COMPRESSOR Filed June' a, 1940 4 snags-sheet 4,

1 75: 9. z I 6 Z.

lNl/EN TOR: W/L LIAM 14 W/S'HART ATTX Patented May 2, 1944 UNITED,STATES PATENT OFFICE i r 2,347,862 w T oomnnsson wiiliamw wishart,ChicagoJll. Application rune a, 1940, Serial No. 339,478"

' 6 Claims. swine-154) This invention relates to improvements incompressors and more particularly to air com' pressors employed inconnection withair tanks wherein it is desired to store airunder apredetermined pressure.

It is an object of this invention to provide an air compressor of therotary type, including iew parts that may be readily assembled and inwhich the rotor may be adjusted within the" stator without taking downthe assembly. It is another object' of this invention to provide arotary compressor in which the direction of rotation of the rotor may bereadily reversed by" a few simple adjustments and in which forcedlubri-' cation is affected without the use of anoil pump.

object of this invention to so locate the discharge ports of the statorthat the air passes therethroughin the direction of rotation oi therotor and thereby provides an improvedform of oil separator. It is afurther object of this invention to provide means for cooling the oilused in the:

forced lubrication system.

With these and other objectsin' ,view, refe ence is made to theaccompanying sheets of drawings which illustrate a preferred'form 01this invention with the understandingthat inin'orv changes may bemadewithout departing from the scope thereof.

In the drawings:

Figure 1 is a top plan view of a preierred form of this air compressorwith parts of the aut0- matic valves shown in horizontal section.

Figure 2 is'a view in vertical transverse section taken on the line 2-4,Figure 1, looking in the direction of the arrows, showing the oil tankin elevation.

. rotation oi. the rotor isreversed.

- Figure 6 'is a Warsaw-wean. vamp transverse section taken on the line6-3, Figure 3 looking in .the direction of the arrows.

Figure 7 is a view partly in section and partlya in elevation taken onthe line 1-1;,Flgure 6,,

looking in the direction or the arrows.

Figure 8 is airagmentary view in horizontalsection taken on the line8-8, Figure, 5, looking in the direction of the arrows. j

Figure 9 is a iragmentary'view oi the end plate partly'in elevation andpartly in: section,

illustrating the air intake duct, showing the rotor reversed indirection of rotation.

Figure 10 is a fragmentary view in horizontal section taken on thelineIll-III, Figure 9, looking in the direction of the arrows.

Figure 11 is a fragmentary view partly in end elevation and partly insection of a modified form 01' air intake valve and air "intake duct.

Figure 12 is a similar view, illustrating a change'in the direction'oithe flow o! the air from the intake valve. when the direction of Figure13 is a fragmentary plan view of the gasket interposed between the airintake valve and end plate, as indicated by the line 13-13, Figure 12,looking in the direction of the arrows.

The air compressor constructed in accordance with this invention and inthe preferred form illustrated upon the drawings includes a rotor ,Imounted eccentrically within a cylindrical stator 2 supported betweenend plates 3 and 4. The

end plate 4 is'of'les's area than the end plate 3 and'is secured theretoby threaded bolts 5 pass- Figure 3 is a view in vertical longitudinal sec-' tion taken on the line 3-3, Figure 1, looking in the direction ofthe arrows, showing the air strainer, automatic valve, and coolingpipes'in elevation.

Figure 4 is a view in vertical section taken on I the line 44, Figure 1,looking in the direction ing through end plates 4 and 3 with thesecuring nuts 8 on the exterior side of the end plate 3,

The end plate 3 also supports a cylindrical airtight casing 1 enclosingthe stator -2 and end plate 4. A driving shaft'fl passes throughopenings provided therefor in end plated, rotor I, and end plate 4 andis connected to the rotor I by a key 9 received in a keyway Iii in therotor I, which key is terminated short of the bottom 0! the keyway ID,as shown in Figure 3. The end plate'3' is provided with an outwardlyextending recessed boss ll for-receiving a ball bearing of any desiredform for the driving shaft and a shaft seal preferably of the formdisclosed in v this applicant's prior Patent No. 2,140,304 of December13, 1938. The end plate 4 is provided with a recessed box 12 forreceiving a ball hearing of any desired form for the end of the drivingshaft 8 and is provided with a cover plate l3 secured thereoversimilarly to the cover plate l4 upon the boss I I. I1. desired, thedriving shaft 8 may be provided withanoflset pulley-l at its,- exteriorend for transmitting power -to rotate the shaft.

The casing 1 is preferably-secured,- inyair-tight;

relation by tap screws IE :to that sideof, the endplate. 3in;,engagement, withgthe stator :2 '50 that all of the working partsxofthe compressor are.

contained withinthe casing 1 and are carriedqby the end plate 3. By thisconstruction;-the-stator- 2 may .be a section of, steel tubing;As;,shown in,

Figure 6,;it is, preferable to;employ flveabolts for one is arranged toengage insagroove H in theand is-discharged into the space" within thecylindricalcasing'l which surrounds the stator 2 and end. plates! It :ispreferableto provide ,the end plate 3 with If: afrverticalyboss22to'cOntain a vertical air duct mounted ;on afbase-platenand contains twoupper surface of the stator to maintain. itsilxed relation to the endplates. By-providing-sa iittle play in the end plates 3 and 4aboutytherbolts 5,1 slight adjustments may bemadebetweemthe.

rotor and stator by looseningthe-nuts Emailing" the adjustment, and thentighteningthe-nuts I all without taking; down the ,,assembled--parts'.--

Ifherotorl mounts a plurality. of spaced-apart" pistons 18 within.apertures 19 provided-therefon in the circumference of: the rotora' Oneend of each piston is pivotally' mounted'in: the body Of-I: the rotorand the outersurface. of thepiston: is; formed'on an arcconcentric'with-therotomso: that as. the rotor passes the point-oftangential, contact with theinner walls .of the stator. the:

outer surface of the pistonrwill act asa continua-e tion of the. rotorsurface. 'As the-rotor passes.

beyondthlspoint, centrifugal ,force will. cause the outer surface of,the piston-to. continue to:

spaced apart chambers 21 and 28 preferably closedby closure plates, and30'. The larger achamber. 21, at'the endzopposite the closure plate 29communicates byan-axial duct 3|, to a vertical passage 327whichisextended through the base plate126.;toregisterwith theupper opening ofthe abduct-23.: .This chamber adjacent the end provided with; the axialduct 3| is also provided upon its. .upperside-.-witha passage 33 tocommunicate with an air strainer 34-of commercial type -which-*isjsupportedinthe boss 35 formed integralhwithjthe casing-25;' The chamber21 is provided-with'a piston- 3S1having an axial projection- '31"adapted'toseats upon the-duct 3| but is normallymaintainedunseated-by acoil spring "interposed between the end of the chamber 21 and :thepiston36., I

Uponarotation of the. rotor I air is then drawn in through the airstrainer 34, passage 33, through 3 the chamberll andductv 3I-into thepassage 32 wipe over the inner surface of, the stator,- and'the q freeend will form an abutment and compressthe air in front of it betweentheinner surface..

of the stator and'thesurface of the rotor. The inner end of. thisabutment is formed so that in the most extended position ofthe piston,the air compressed in advance of the abutment-twill enter the, recessesIS in the rotor: and will assist the centrifugal force in holdingthepiston in engagement with the walls of the rotor. I

As shown in Figures 5 and,6, the rotor moves in a clockwise directionwiththe center of rotation of the rotor above the axisof the stator andprovision is made to admit atmospheric airinto the space between theouter surface of the ,rotor and inner surface of the stator through aport 20 below and to the rightof the centers thereofand the air,compressed betweengpistons is discharged through ,a plurality ofdischarge ports 2| in the stator preferably diametrically opposite theair inlet port. The air; intake port, 2045 formed in the end plate 3 sothat atmospheric air is admitted to the-space between the rotor andstator at right angles to the direction ofrotation of the rotor. Theconnection between" the air intake port 20 and the atmospheric air willhereinafter be described. This invention contemplates the provision of aplurality of similar spaced apart discharge ports-2| arranged parallelto each other which pass at an angle through the body of the'stator sothat the centers of the openings'of the ports on each side of the statorlie in planes parallel to the axis. of the stator. and it is preferableto construct the ports so that the longitudinal center line of the innersurface first wiped over by a piston will be in a plan approximatelytangential to the rotor, as shown in Figures 6 and 7, so that the airunder pressure is caused to flow through the walls of the stator in thedirection of the movement of the pistons registering with the airduct-23 to the air intake port201intheendplate 3'and the air within thestator is discharged under pressure through the discharge ports 2i intothe interior of the casing 1., The-air'under pressure is discharged fromthecasing 1 througlra checkvalve 39 mounted in a valve casing 40 carriedupon the exterior of the casing land communicating with the interiorthereof :through the. duct.v The other end of the checkrvalve.casingisconnected to a pipe 42 leading-t0 an air tank-or otherinstrumentality where air-under pressure is desired. 1

When the predeterminedpressure within the air tank, not shown, isreached, in order that the rotor may idle it is necessary to close theintake side offthe compressor to the atmosphere and at the same time,relieve the accumulated pressure within-thepcasing 1. In order toaccomplish this the piston 33 is provided with'an axial projection whichwill engage the end plate 29 of the cylinder 21 under the tension of thespring 38 when the duct3l is uncovered to allow that end of the pistonto uncover the opening of a duct 44 passing through-the valve casing 25to communicate with the smaller chamber 28. The smaller chamber 28mounts a piston 45' having a piston rod 43 passing through a perforatedclosure plate 41 for Sylphon mounted in a bracket 49 carried upon thebase plate 26 so that upon expansion and contraction of the Sylphon 48the piston 45 will be, reciprocated. The piston 45. is provided with anannular groove 50 which is adapted to register with the passageway .inthe casing 25 when the Sylphon has been expanded to move the piston tothe end of its travel in the direction of the end plate 30 and at thesame time, to register with a passageway 5i opening through the sidewall of the valvecasing 25. This passageway 51 is in communication witha pipe 52 which joins a-T-connection 53, the other arm of which isconnected by a pipe 54 to the interior of the Sylphon 48. The leg of theT-connection is Joined to a pipe 55. It is preferable to connect thecheck valve casing 48 upon the cylindrical casing 1 of the compressor tothe air tank or other disposition of the air under pressure through thepipe 42 by a T-connection 56 and the pipe 55 is joined to theT-connection so that when the predetermined pressure is reached theadditional pressure passing through the T-connection 56 upon the checkvalve casing 48 and pipe 55 will follow through the T-connection 53 andpipe 54 to the interior of the Sylphon which will cause it to expand andmove the piston 45 to the end of its travel tocause the annular groove50 therein to register with. the air passages 5| and 44 in the valvecasing 25 so that the pressure will be transmitted from the T-connection53 through pipe 52, passageway 5|, chamber 28, passageway 44 to the rearof the end of piston 36 within the chamber 21 which will move the pistonagainst the tension of the spring 38 to cause the projection 31 to seatupon the duct 3| and close the passageway 32 to the atmosphere throughthe air strainer. In order to relieve the pressure within the casing I,an annular groove 51 is provided in the piston 36 and so arranged thatwhen the increased pressure has seated the extension of the piston 31about the duct 3| the annular groove will communicate with a passageway58 in the side of the valve casing 25 and at the same time, communicatewith a duct 59 in the wall of the valve casing 25 which passes below thechamber 28 to communicate with a pipe 63 which passes through aconnection 6| on the side of the casing 1 so that the pressure withinthe casing 1 may be equalized through the pipe 68, duct 59, annulargroove 51 in the piston 36, and pass to the atmosphere through thepassageway 58, as shown in Figure 4, whereupon the rotor may idle.

In order to adjust the pressure required to expand the Sylphon 48 a coilspring 62 is interposed between the end of the Sylphon 48 in engagementwith the piston rod 46 and an adjustable abutment 63 mounted in abracket 64 carried on the base plate 26. This adjustable abutment 63 isin the form of an exteriorly screw-threaded cylindrical member throughwhich the piston rod 46 passes and is provided with a knurled head 65and the interior of the bracket 64 is correspondingly screw-threaded toengage the threads on the abutment whereby the rotation of the knurledhead 65 'will advance or retract the abutment to increase or decreasethe tension of the spring 62.

wise direction. The rotor may be mounted to rotate in counter-clockwisedirection by removing the casing I from theend plate 3 andthen removingthe bolts 5 and end plate 4. The rotor and stator are then removed fromthe shaft 8 and replaced in reverse position thereon and the partsreassembled. However, provision must be made for the atmospheric air'tobe delivered to the space between the rotor and stator through a port onthe opposite side of the vertical center from the intake port 26.Provision for this is made by forming a horizontal boss 66 upon theexterior of the end plate extending from the bottom of the boss 22 tocontain a similar air passage 61 which is shown in Figure 3 as joiningthe passageway 23. take port 68 is formed in the end plate 3communicating with the horizontal passage 61 in the proper relation toallow air to pass therethrough when the rotor is rotated in acounterclockwise direction. Figures 3 and 8 show openings formed in theapex of the bosses 22 and 66 and-inthe horizontal boss 66 opposite theintake ports 25 and 68, which openings are closed by threaded closuremembers 68 and 10. Whenthe rotor is positioned to'rotate in a clockwisedirection the closure 18 which is provided with an extension plugadapted to close" the intake port is inserted through the opening in theboss to seal the'intake port 68 while the closure 68 merely closes theopening in the boss. When the rotor has been positioned to rotate in acounterclockwise dlrection these closures 69 and ID are reversed, asshown in Figure 10, so that the intake port 20 is sealed and the airintake port 68 r is open to communicate with the atmosphere When thepressure recedes below the predetermined amount, the spring 62 will actupon the- Sylphon 48 to retract the piston to the other end of itstravel and in so doing. will cause the end of the piston 45.to uncoverthe passageway 44 and close the passageway 5|. The end plate 30 isprovided with an axial passageway 36 so that when the piston 45 is inthe position shown in Figure l and the spring 38 unseats the duct 3| theair between the end of the piston 36 and the end plate 29 will passthrough the duct 44 into the chamber 28 and beed out through the axialpassageway 30.

The provision of the discharge ports 2| through the walls of the stator2 and the manner of mounting the stator and rotor upon the end plate 3allow a reversal of the movement of the rotor with but few adjustments.As shown in Figures 3. 5 and 6, the rotor is rotated in a clock throughair passages 61 and 23, as shown in Figure 9.

While this manner of reversing the flow of atmospheric air totheinterior of the stator is illustrated in connection with Figures 1, 3and 5 of the drawings whereby the change of flow of air.

is regulated by the position of the plug 68, yet the same result may beaccomplished in a slightly different manner as shown in Figures 11, 12and 13. Figure 11 shows two vertical bosses on the end plate'3, one boss22 forming the vertical air duct 23 the same as in Figure 3 and asimilar boss 12 forming a similar air duct 13 arranged on the other sideof the vertical center of the rotor. The air duct 23 communicates withthe air intake port 28 and the air duct 13 communicates with the airintake port 68. In this figure, the rotor is shown in dotted lines asrotating in a clockwise direction and the automatic suction or intakevalve casing 25 is mcunted on the base plate 26 so that the air passage32 in the valve casing 33 opens above the axis of the rotor. The baseplate 26 is spaced apart from the support 24 of the end plate 3 by agasket 14 which is provided with an elongated longitudinal slot 15 soarranged that when secured between the support 24 and base plate 26 bythe tap screws 16 the slot 15 will form a means of communication betweenthe air passage 32 in the valve casing 25 and the air duct 23, as shownin Figure 11. In this form of construction, when it is desired toreverse the flow of air when the rotation of the rotor is reversed thebase plate 26 is detached and the gasket is reversed, as shown in Figure12. and the base plate again secured whereupon the flow of air will bedirected into the air duct 13 when the rotor rotates in counterclockwisedirection.

This invention contemplates lubricating the moving parts of thecompressor by providing an As shown in Figure 8, an inaxial opening I1in the cover plate l3 for the bearing of the shaft 8 in the end plate land by providing an axial duct 18 in connected with a radial duct 19opening through the circumference of the shaft 8 vinto the keyway it ofthe rotor I. It is preferable to provide recesses 80 and 8| in the endsof the rotor I about the shaft 8. Abath of oil or other lubricant isintroduced into the casing I which will surround the stator 2 and endplate 8, which bath is maintained at a normal level so that the pressurecreated within the casing I will force the oil through the axial opening11 to lubricate the bearings of the shaft 8 behind the cover plate l3,enter the axial duct 18 in the shaft 8,.pass through the radial duct 19through keyway l8, and then into the recesses 80 and 8| to lubricate theends of the rotor l in wiping over the end plates 3 and 4 and from therecess 8| in the end of the rotor l to lugbricate the bearings of theshaft 8 in the boss I l. The lubricant will be prevented from escapingfrom the boss Ii by the seal arranged about the 1 shaft 8.- As thepistons l8 traverse the circumference of therotor I, the pivotedportions there-/ of will'be lubricated by the oil forced between theends of the rotor and the end plates .3 andl.

The lubricant or oil is supplied to the interior of thezcasing I from anoil cupor reservoir 82 mounted'upon the upper surface, of the casing 1and communicating with the interior thereof by a pipe-88 terminatingjust below the axial opening 11 in the cover plate IS. The cup orreservoir 82 is provided with a sealed cover 84 and the opening of the.cup into the pipe 88 isprovided with a spring-pressed valve 85 whichnormally acts to close the opening. The cover 84 is providedwith a screwplug 86 in axial alignment with the oil that end of the shaft are eachpassed through apertures provided therefor in the'end of the casing I,which apertures are provided with seals 93 and sealing plugs 94. Thecooling coil may act to circulate a cooling fluid of either liquid orair as may be desired, and the cooling fluid may be circulated throughthe coil in any desired manner and therefore, this means is' notillustrated upon the drawing.

By the construction contemplated and above described, it is readily seenthat the compressor may be assembled at the factory to provide either aclockwise or a counterclockwise rotation to the rotor and the directionof rotation of the rotor may be readily and easily changed in the field.

Likewise, it is obvious that, ifdesired, the top of the support 24- maybe recessed to connect the passage 32 in the suction valve casing 25 toboth of the air ducts 23 and I3 and the bosses 22 and 12 provided withopenings aligned with the intake ports 28 and 68 to be closed withclosures 69 and 10 in the manner described and shown in Figures 8, 9 and10, in lieu of the gasket 14 having the slot 15, and thereby avoids thenecessity of removing the base plate 26 of the 'valve pipe 88 and isprovided with an axial depending .Y

post 81 so arranged to depress the stem 88 of the valve-85 when the plug86 is seated in the cover 84 to allow oil to flow as needed into thecasin l and maintain the level of the oil bath for the properlubrication of the moving parts, so that oil may be poured into the 'cup82 through the opening in the .cover when the plug 86 is removed.

It has been found that when air under pressure containing particles-ofoil in suspension impinges u'pon polished surfacessuch aschromium-plated metal, the oil will be separated therefrom and willdrain off the polished surface. By arranging the discharge. ports 2| ofthe compressor in the walls of the stator 2,.it is possible to provide abaiiie of polished or chromium-plated metal in the path of the air.under pressure as it leaves the discharge ports 2 I. As shown inFigures 5, 6 and '7, it is preferable to provide a bailie 89 in the formof a curved plate extending transversely of the stator 2 above thedischarge openings 2| with its furthest edge secured to the outersurface of the stator 2 and with its inner surface polished.

. being raised beyond a predetermined degree. This inventioncontemplates the provision of a cooling coil 99 within the casing 1immersed in the oil bath contained therein. As shown in Figure 3, theintake 9| and exhaust 92 of the cooling coil casing 25 as described andshown in Figures 11 and 12t It is also obvious that, if desired,reciprocating vanes may be substituted in the rotor for thecentrifugally operated pistons i8 without departing from the scope ofthis invention.

It is to be noted that the bath of the lubricant in the casing 1 ismaintained at a level to be forced by the air under pressure within theeasing lthrough the opening I1 in the end plate l8 by terminating thelubricant supply pipe 83 just below the desired level whereby wheneverthe lubricant uncovers the opening 11 the lubricant will flow from thereservoir 82 through the pipe 83 until the level of the bath again sealsthe open end of the supply pipe.

What I claim is: I

1. A rotary compressor including a driving shaft, a rotor mountedthereon, a cylindrical stator surrounding the rotor, an end plate havinga bearing and a seal through which the shaft passes, a second smallerend plate provided with y a bearing to receive one end of the shaft, anairtight casing secured to the first end plate surrounding in spacedapart relation the stator and smaller end plate, means for assemblingthe rotor.- and stator between the end-t plates passing through thefirst end plate to engage the second end plate, said means alsosupporting the stator, and means upon the first end plate cooperatingwith similar means upon the second end plate for adjusting the relationof the stator to the rotor without removing the air-tight casing whereinthe said assembly means includes bolts passing through both end plates,some of said bolts supporting the stator thereon; nuts threaded upon theends of the-bolts upon the exterior of the first end plate, and whereinthe adjusting means includes the provision of suificient clearance aboutthe bolts in the end plates to accomplish the adjustment.

2. A rotary air compressor including a rotor.

a cylindrical stator surrounding the rotor said means assembling thesmaller end plate, rotor and stator upon the first end plate,- an airintake port in the first end plate to admit air into the stator, asecond normal y closed air intake port in the first end plate equallyspaced apart from the vertical center line of said end plate and on theside of the center line opposite the first intake port, and a pluralityof discharge ports in the wall of the stator above the said air intakeports, whereby the rotor and stator may be removed from between the endplates, reversed and reassembled and upon removing the closure of thesecond air intake port and closing the first air intake port thecompressor will operate with the rotor rotating in a reversed direction.

3. The structure of claim 2, wherein the detachable assembly meansincludes a plurality of bolts passing between the end plates about theexterior of the stator, two of which are positioned to support thestator in proper relation to the air intake ports in the end plate, anda third bolt passing through a grove in the outer surface of the statormidway between the stator supporting bolts to insure the passage of airthrough one of the intake ports depending upon of the direction ofrotation of the rotor by aligning the air intake ports with the interiorof the stator.

4. The structure of claim 2, wherein the first intake port is connectedby an air duct formed in the first end plate to an air inlet valve, andwherein said air duct is continued to the second normally closed airintake port.

5. The structure of claim 2, wherein the first intake port is connectedby an air duct formed in the first end plate to an air inlet valve, andwherein said air duct is continued to the second normally closed airintake port, and wherein the end plate is perforated in alignment withthe first intake port and perforated in alignment with the second intakeport, said perforations adapted to be closed by similar plugs threadedthereinto, one of said plugs provided with an extension adapted toclose'and seal the oppositely disposed air intake port.

6. A rotary compressor including a driving shaft, a rotor mountedthereon, a cylindrical stator surrounding the rotor, an end plate havinga bearing and a seal through which one end of the shaft. passes, asecond smaller end plateprovided with a bearing to receive the other endof the shaft, an air-tight casing secured to the first end platesurrounding in spaced apart relation the stator and smaller end plate,means for assembling the rotor, stator and smaller end plate upon thefirst end plate, an air intake port in the first end plate, airdischarge ports in the wall of the stator between the end plates, alubricating system for the moving parts of the compressor, and an oilseparator upon the eX- terior of the stator including a curved platemounted transverse of the stator presenting its concave surface to thedischarge ports, said concave portion having a highly polished surfacewhereby the particles of. lubricant sepa rated from the air uponstriking the separator will quickly drain therefrom.

WILLIAM W. WISHART.

